In the restaurant scene near the beginning, when the snotty customer asks for bread, Andrew Largeman replies they have none and explains this is because it is a Vietnamese restaurant. In fact, because of the French colonization of Vietnam in the mid 19th Century, French baguettes are a common staple in Vietnamese cuisine and any good Vietnamese restaurant would most likely have them in their kitchen.
At a Jewish funeral, the casket would be lowered completely into the ground. The first shovel full of dirt would be lifted with the shovel head upside down to show reluctance to fulfill the mitzvah of burying the dead. After the first throw of dirt, the shovel is turned right side up and used. Then it is passed to others and the family and friends do most of the refilling. When Andrew's father is putting the dirt on the casket it is above ground and he has the shovel right side up.
About 10 minutes into the film, when Andrew Largeman is riding a motorcycle without head (helmet) or eye (goggle/glasses) protection, he is stopped by a Police Officer for speeding (only). New Jersey has both helmet and eye protection laws.
When Largemen first enters his father's office after the funeral to talk about his headaches, his father's glasses alternate locations on the desk. In some shots they are open on the table, in others they are not on the desk at all.
When Sam and Andrew are in the bathtub, there is a small cup behind Sam. Later, when she gets up to get a cup to catch Andrew's tear, the cup behind her has disappeared and she puts the new cup where the "ghost" cup was.
When Mark, Andrew, and Sam are walking through the "backrooms" of the hotel, we see a man get out of their way by ducking behind a soda machine on the right-hand side. In the next shot, the man has disappeared.
In the scene at the breakfast table the night after the party, in one shot the milk jug is placed so that the label is not shown, in the next shot the label is shown and in the third shot, the label is missing again.
After Andrew, Mark and Sam leave the ark wearing garbage bags
to protect them from the rain, you can see that Sam's pink sweater is dry under the garbage, but was a dark, wet pink when they were inside the ark from being out in the rain earlier. The sweater could not have dried while they were inside the ark.
When Sam asks the bellhop why he assumes the girl they were watching was a prostitute, she mentions a line about Julia Roberts and the door behind her is left slightly open using the door lock hinged out. In the next shot and preceding shots before that the door is shut.
When Andrew, Mark, and Sam have just arrived at the quarry and are walking toward us, you can just see headlights of an arriving car at the very edge of the frame in the background that looks like it pulls up beyond the motorcycle. When we cut back to the shot, the car is gone.
When Andrew walks into his father's bedroom, his father is asleep with his head turned to his right. When the camera pans out to both of them, his father's head is now turned to his left without movement.
The first time Andrew goes to look at the tub where his mother died (when he adjusts the dripping faucet) there is a white handicapped railing attached to the side of the tub, the second time he goes there (when he is sitting in the tub with Sam) there is no longer a handicapped rail.
In the pool scene when everyone (except for Andrew) jumps into the pool, everyone emerges from the water during the wide shot, including Sam. However, on the next close-up of Sam it shows her still underwater, before submerging.
In the boat, Albert's wife Fay starts off with a tea mug with a bird on it and Albert has a white mug with the periodic table on it, in the next shot the mugs are switched and in the final shot, the mugs are back to their original owners.
When Mark and his mother are talking about the Real Estate tapes, when Mark says "You know what? I do apply myself every day, Mom." The shot cuts mid-sentence from a mid-shot with Mark holding his cigarette near his lap to a closer shot of Mark holding the cigarette near his head.
At the end, when Andrew and Sam are sitting on the stairwell in between the two escalators, both are moving in the establishing shot, but the right one is stopped in the close-up shot, and then it's moving again when we see just Andrew.
When Sam and Andrew first meet in the waiting room, there is a close-up of Sam's face smiling broadly, then relaxing her expression. She appears to do this twice, in exactly the same way, because the shot of her smiling the second time, is clearly just played/looped again, instead of her really smiling twice.